1. Field of the Invention
The present invention relates to a cleaning device for cleaning a surface of a disc type recording medium on which information is recorded and/or reproduced by the use of laser beam.
2. Related Background Art
Various recording media have been used for an information recording/reproducing apparatus in which information is recorded or reproduced on the recording media by using a laser beam. In such recording media, for example, there are recording media such as compact discs, video discs, CD-ROM or the like only for information reproduction, such recording media on which information can be additionally recorded according to the phase change of a metal, the shape of a pit or the like, and such recording media on which information can be re-written by thermal magnetic (optical magnetic) or organic materials. These practical recording media have been protected by providing a plastic layer or glass substrate having a thickness of about 1 to 1.5 mm on the recording layer. However, there has been posed such a problem that when a dust or the like sticks to the surface of the recording medium so as to dirty the surface of the medium, the incidence of laser beam is caused to be blocked, and as a result the recording or reproduction is degraded. Therefore, it is necessary to regularly clean the surfaces of the recording media upon which laser beams are incident, and so various cleaning devices have been proposed.
Now, an example of conventionally proposed cleaning devices will be illustrated with reference to FIG. 7. In FIG. 7, numeral 81 denotes a cleaning member, numeral 82 denotes a recording region, numeral 83 denotes a disc type recording medium, and numeral 84 denotes the radial width of the recording region. In this structure, cleaning is carried out by the rotation of the cleaning member 81, having a ring shape with an inner diameter greater than the recording regional width (84) of the disc type recording medium (83), in the direction of arrow. At this time, it is effected so that the frictional direction is as perpendicular as possible to the circular direction. That is, the frictional direction is directed toward the radial direction of the recording medium. This is because the formation of flaws not less than a medium negatively influences the recording/reproducing.
However, it is difficult to apply in practice the above structure as a cleaning device in view of the cartridge structure of the recording medium (Recording media have been conventionally placed in each cartridge case to protect it from dust). This cartridge case has a small window which opens on recording, reproducing or erasing information to expose a part of the recording medium to the outside. Because the size of the small window on the cartridge case is limited, it is not easily convenient to clean the surface of the recording medium through that small window.